Ethylbenzene is a feedstock for the commercial preparation of styrene monomer. Commercially, ethylbenzene is made by alkylating benzene. Benzene, however, is expensive and routes to styrene utilizing a non-benzene feedstock would be economically desirable.
Butadiene is becoming increasingly available in economic amounts. A process route that would lead from butadiene to ethylbenzene and/or styrene would be quite useful. It is known in the literature to dimerize butadiene via the Diels-Alder reaction to 4-vinylcyclohexene. A catalyst that would effectively convert vinylcyclohexene to ethylbenzene and/or styrene would be very useful in a commercial process starting with butadiene and leading to styrene monomer. Catalysts are known for the conversion of vinylcyclohexene to ethylbenzene. See, for example, U.S. Pat. No. 3,903,185 issued Sept. 2, 1975 to Vogel et al, U.S. Pat. No. 4,029,715, issued June 14, 1977 to Rieve et al, and U.S.S.R. Pat. No. 279,614, issued Nov. 24, 1970 to Sterlitamak Chemical Works. Although the art teaches the use of potassium salts as promoters for Group VIII transition metal catalysts, the art does not teach the use of a potassium salt as a dehydrogenation catalyst per se. In fact, the art teaches that potassium salts supported on alumina are isomerization catalysts rather than dehydrogenation catalysts.